CN113422421A - Battery device, power supply system and related control method - Google Patents

Battery device, power supply system and related control method Download PDF

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Publication number
CN113422421A
CN113422421A CN202110585530.7A CN202110585530A CN113422421A CN 113422421 A CN113422421 A CN 113422421A CN 202110585530 A CN202110585530 A CN 202110585530A CN 113422421 A CN113422421 A CN 113422421A
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China
Prior art keywords
converter
voltage
battery
control unit
threshold value
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CN202110585530.7A
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Chinese (zh)
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CN113422421B (en
Inventor
许勇枝
苏先进
易龙强
曾奕彰
王定富
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Zhangzhou Kehua Technology Co Ltd
Kehua Data Co Ltd
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Zhangzhou Kehua Technology Co Ltd
Kehua Data Co Ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00302—Overcharge protection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/007—Regulation of charging or discharging current or voltage
    • H02J7/00712—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H02J7/007182—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters in response to battery voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention discloses a battery device, a power supply system and a related control method, wherein the battery device is electrically coupled with an inverter device to form the power supply system, and the power supply system comprises a plurality of battery modules, a plurality of DC/DC converters and a control unit; the DC/DC converters are bidirectional DC/DC converters, the low-voltage side of each DC/DC converter is connected with a battery module, and the high-voltage sides of the DC/DC converters are connected in parallel with a common end and are connected with the converter device through the common end; when the voltage of the public end is lower than a first threshold value, the control unit controls each DC/DC converter to work in the discharging direction; and when the voltage of the public end is higher than a second threshold value, controlling each DC/DC converter to work in the charging direction. The battery device and the power supply system have higher personnel safety when the battery is maintained and operated, reduce the complexity of the battery device on a communication layer and a control layer, and are suitable for expanding the capacity of the power supply system.

Description

Battery device, power supply system and related control method
Technical Field
The present invention relates to the field of battery and battery-powered technologies, and in particular, to a battery device, a power supply system, and a related control method.
Background
Currently, the UPS is widely adopted. In the event of a mains power anomaly, the UPS typically switches to a battery-powered state to ensure uninterrupted power supply to the load. As the load level increases, the output power of the UPS also needs to increase, which requires that the output power of the battery pack is also matched in the battery-powered state.
In the conventional UPS, the battery assembly is generally composed of a plurality of battery packs, and when capacity expansion is required, the battery assembly is generally implemented by connecting more battery packs in series or by using a battery pack with more single batteries. However, the voltage gain of the DC/DC converter inside the UPS is not large, so that more batteries need to be connected in series during capacity expansion, which results in higher output voltage of the battery pack, and this has a certain influence on the safety of personnel operating and maintaining the battery pack.
Disclosure of Invention
The present invention is directed to overcome at least one of the drawbacks or problems of the related art, and provides a battery device, a power supply system and a related control method, where the power supply system is suitable for capacity expansion by using the battery device, and has better personnel safety.
A first aspect of the invention provides a battery device for electrical coupling with an inverter device; it includes: each battery module comprises a plurality of battery cell units which are connected in series; a number of DC/DC converters each configured as a bidirectional DC/DC converter; the low-voltage side of each DC/DC converter is connected with a battery module, and the high-voltage sides of the DC/DC converters are connected in parallel with a common end and are connected with the converter device through the common end; the control unit is used for controlling each DC/DC converter to work in a discharging direction when the voltage of the common terminal is lower than a first threshold value; when the voltage of the public end is higher than a second threshold value, controlling each DC/DC converter to work in the charging direction; wherein the first threshold is less than or equal to a second threshold.
Further, the method also comprises the following steps: the voltage collector is used for collecting the voltage of the public terminal; the control unit comprises a plurality of controllers corresponding to the DC/DC converters, and each controller is connected with the voltage collector to obtain the voltage of the public terminal and is used for controlling the working direction of the corresponding DC/DC converter.
Further, each controller controls the working direction of the corresponding DC/DC converter by modulating the duty ratio of the PWM signal.
Further, the maximum output voltage of each battery module is lower than 65V; the number of the battery cell units in each battery module is the same, each battery cell unit is composed of two single batteries which are connected in parallel, and each single battery is a lithium battery.
A second aspect of the present invention provides a control method of a battery device as set forth in the foregoing technical solution; the method comprises the following steps: acquiring the electric quantity of each battery module and the voltage of the public terminal; controlling the working state of each DC/DC converter according to the public terminal voltage and the electric quantity of each battery module; when the voltage of the public end is lower than the first threshold value, controlling each DC/DC converter to be started and work in a discharging direction; when the voltage of the public end is higher than the second threshold value, controlling each DC/DC converter to be started and work in the charging direction, and when the battery module is fully charged, controlling the corresponding DC/DC converter to be closed; and when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each DC/DC converter is kept.
A third aspect of the present invention provides a power supply system, comprising: a battery device as defined in the above-mentioned claim; the control unit is defined as a first control unit, the DC/DC converter is defined as a first DC/DC converter, and each first DC/DC converter is used for realizing voltage conversion between the output end of the corresponding battery module and the common end; the common terminal constitutes an external connection terminal of the battery device; the converter device is provided with a battery end and comprises a direct current bus, a second DC/DC converter and a second control unit; the battery end is connected with the external connecting end of the battery device; the second DC/DC converter is a bidirectional DC/DC converter, and two sides of the second DC/DC converter are respectively connected with the direct current bus and the battery end and used for voltage conversion between the direct current bus and the battery end; the second control unit is used for controlling the second DC/DC converter to be kept on.
Further, the converter device further comprises an AC/DC converter and a DC/AC converter; the direct current sides of the AC/DC converter and the DC/AC converter are both connected with the direct current bus, the alternating current side of the AC/DC converter is connected with an alternating current power supply, and the alternating current side of the DC/AC converter outputs alternating current; the high-voltage side of the second DC/DC converter is connected with the direct-current bus, and the low-voltage side of the second DC/DC converter is connected with the battery end.
Further, the alternating current power supply at least comprises commercial power; the second control unit acquires a mains supply state, controls the second DC/DC converter to work in a charging direction when the mains supply is normal, and controls the second DC/DC converter to work in a discharging direction when the mains supply is abnormal.
Further, a voltage collector of the battery device is defined as a first voltage collector; the converter device also comprises a second voltage collector which is used for collecting the voltage of the direct current bus; the second control unit is a second controller and is connected with the second voltage collector to obtain the voltage of the direct current bus; when the voltage of the direct current bus is lower than a third threshold value, the second DC/DC converter is controlled to work in the discharging direction; when the voltage of the direct current bus is higher than a fourth threshold value, the second DC/DC converter is controlled to work in the charging direction; wherein the third threshold is less than or equal to a fourth threshold.
A fourth aspect of the present invention provides a method for controlling a power supply system, the power supply system being as defined in the foregoing technical solution; the method comprises the following steps: the second control unit controls the second DC/DC converter to be kept on; the second control unit acquires direct-current bus voltage; the second control unit controls the working direction of the second DC/DC converter according to the voltage of the direct-current bus; when the direct-current bus voltage is lower than the third threshold, controlling the second DC/DC converter to work in a discharging direction; when the voltage of the direct current bus is higher than the fourth threshold value, controlling the second DC/DC converter to work in a charging direction; when the direct current bus voltage is between the third threshold value and the fourth threshold value, the working direction of the second DC/DC converter is kept; the first control unit acquires the electric quantity of each battery module and the public terminal voltage; the first control unit controls the working state of each first DC/DC converter according to the public terminal voltage and the electric quantity of each battery module; when the voltage of the public end is lower than the first threshold value, controlling each first DC/DC converter to be started and work in a discharging direction; when the voltage of the public end is higher than the second threshold value, controlling each first DC/DC converter to be started and work in the charging direction, and when the battery module is fully charged, controlling the corresponding first DC/DC converter to be stopped; and when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each first DC/DC converter is maintained.
Compared with the prior art, the invention has the beneficial effects that:
(1) the battery device comprises a plurality of DC/DC converters, and each DC/DC converter is coupled with the corresponding battery module to convert the output voltage of the battery module and then output the converted voltage in parallel, so that the capacity expansion of a power supply system applying the battery device is not required to be realized by greatly improving the output voltage of the battery module. In other words, under the condition that the battery module outputs lower voltage, the battery device can still keep certain output voltage during working so as to meet the requirement of a power supply system; when maintenance is needed, the battery module can be maintained safely due to the fact that the output voltage of the battery module is not high. Therefore, the structure effectively improves the personnel safety of the battery device during maintenance and operation.
Moreover, each battery module of the battery device is correspondingly provided with the bidirectional DC/DC converter, and on the basis, the invention further provides the control unit which can control the working direction of each DC/DC converter and match the operation requirement of the converter device only according to the simple comparison between the voltage of the common end formed by connecting the high-voltage sides of the DC/DC converters in parallel and the preset threshold value. Specifically, the reason is that the battery device is electrically coupled with the inverter device to discharge or charge the inverter device, and the battery device is connected with the inverter device through the common terminal to form the power supply system to supply power to the outside, so that the operation requirement of the inverter device can be mapped to the common terminal voltage, and the control unit can obtain the operation requirement of the inverter device and control actions corresponding to the operation requirement only according to the common terminal voltage to match the operation requirement.
In other words, when the battery device is actually applied, the control of the DC/DC in the battery device can be independent of the control of the converter device, and the battery device can be matched with the operation requirement of the power supply system without establishing a direct communication connection with the converter device through an industrial control bus and giving a complex control algorithm, so that when the number of the DC/DC converters in the battery device is large, the battery device is particularly suitable for reducing the complexity of the communication layer and the control layer when the battery device is actually applied, and reducing the difficulty of field wiring, thereby providing a better material basis for the capacity expansion of the power supply system applying the battery device.
(2) The voltage collector is arranged, the voltage of the public terminal can be stably collected and transmitted to the control unit, and the control unit can obtain the voltage of the public terminal; the control unit is configured to comprise a plurality of controllers respectively corresponding to the DC/DC converters, so that the software and hardware cost of the control unit is reduced.
(3) The duty ratio of the PWM signal is modulated to control the working direction of each DC/DC converter, so that the method is applicable to most DC/DC converters, and is wide in application and mature in technology.
(4) Each electric core unit quantity in the battery module is the same, can prevent the emergence of the circulation condition of parallelly connected to a certain extent. The maximum output voltage of each battery module is lower than 65V, and the safety of personnel maintenance is guaranteed. The battery cell unit is composed of two single batteries which are connected in parallel, so that the current level of the battery cell unit which can be loaded is improved, and the discharge performance of the battery device is improved. The cell unit is composed of lithium batteries, in other words, the single batteries in the cell unit are all lithium batteries, so that the service life is long, and the discharge is stable.
(5) The control method of the battery device takes the internal control unit as a main control party on the basis of the materials of the battery device, controls the working state of each DC/DC converter by acquiring the electric quantity and the common terminal voltage of each battery module, and inherits all the advantages of the battery device. In addition, the control method further limits that when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each DC/DC converter is kept unchanged, so that the DC/DC converters have certain buffer space for direction switching when the common terminal voltage fluctuates, and the stability of the battery device during working is improved. Furthermore, the battery can be prevented from being overcharged by acquiring the electric quantity of each battery module to turn off the corresponding DC/DC converter when the battery module is fully charged, and the battery control method is particularly suitable for lithium batteries.
(6) The power supply system comprises the battery device and the converter device, the converter device is connected into the battery device so that the battery module is connected to the direct current bus through two stages of DC/DC, certain output voltage can be ensured to meet the requirements of the power supply system when the battery module outputs lower voltage, and personnel can maintain and operate the battery module relatively safely, so that the power supply system takes the battery device as a material basis, inherits and realizes all the advantages of the battery device, and is suitable for capacity expansion. In addition, the battery device is connected to the battery end of the converter device instead of a direct current bus, the existing converter device is not required to be modified, and the universality is good.
Moreover, when the power supply system of the invention applies the battery device, the key configuration is also performed on the converter device, that is, the second control unit controls the second DC/DC converter to keep on when the converter works, so that the DC bus voltage suitable for reflecting the operation requirement of the converter device can be transmitted to the common terminal voltage of the battery device through the second DC/DC converter, thereby ensuring that the battery device can obtain the effective common terminal voltage capable of mapping the operation requirement of the converter device at any time, and the first control unit effectively controls the first DC/DC converter to match the operation requirement of the converter device, thereby ensuring the stable operation of the power supply system.
(7) The inverter device has an AC/DC converter and a DC/AC converter therein, so that the power supply system substantially constitutes an UPS power supply system suitable for capacity expansion, and can stably supply power to a load in a battery power supply state.
(8) The second control unit directly acquires the state of the mains supply to control the working direction of the second DC/DC converter, and the response is quick.
(9) The second control unit controls the working direction of the second DC/DC converter by collecting the voltage of the direct-current bus through the second voltage collector, and the stability is high.
(10) The control method of the power supply system is characterized in that on the basis of the materials of the power supply system, a first control unit and a second control unit of the power supply system are respectively used as main control sides of a battery device and an inverter device, and a second control unit keeps a second DC/DC converter on to respectively control the working state of each first DC/DC converter and the working direction of the second DC/DC converter, so that all advantages of the battery device and the power supply system are inherited.
In addition, the control method further limits that when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each first DC/DC converter is kept unchanged, so that the DC/DC converters have certain buffer space in the direction switching process when the common terminal voltage fluctuates, the stability of the battery device in the working process is improved, and the advantages are also suitable for the control of the converter device. Furthermore, the battery can be prevented from being overcharged by acquiring the electric quantity of each battery module to close the corresponding first DC/DC converter when the battery module is fully charged, and the method is particularly suitable for lithium batteries.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a topology diagram of a battery device according to an embodiment of the present invention;
fig. 2 is a topology diagram of a power supply system according to an embodiment of the present invention.
Description of reference numerals: a battery device 10; a battery module 11; a first DC/DC converter 12; a first controller 13; a first voltage collector 14; a deflector 20; an AC/DC converter 21; a DC/AC converter 22; a second DC/DC converter 23; a second controller 24; and a second voltage collector 25.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are presently preferred embodiments of the invention and are not to be taken as an exclusion of other embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In the claims, the specification and the drawings of the present invention, unless otherwise expressly limited, the terms "first", "second" or "third", etc. are used for distinguishing between different items and not for describing a particular sequence.
In the claims, the specification and the drawings of the present invention, the terms "including", "having" and their variants, if used, are intended to be inclusive and not limiting.
In the claims, the specification and the drawings of the present invention, unless otherwise specifically limited, the term "connected", as used herein, may include a direct connection or an indirect connection; the term "coupled", as used herein, means that the two electrical modules have a particular circuit function when connected.
Referring to fig. 1-2, an embodiment of the present invention first provides a battery device 10, wherein the battery device 10 is configured to be electrically coupled to an inverter device 20 for discharging or charging the inverter device. In this embodiment, the converter device 20 is a part of the UPS power system excluding the conventional storage battery, that is, a part including rectification, inversion, and boosting, and its specific structure will be described in detail below. It goes without saying that, after the inverter device 20 of the present embodiment is connected to the battery device 10, the two devices together form a UPS power supply system to provide uninterrupted power supply.
Referring to fig. 1 and back to the battery device 10 of the present embodiment, it includes a plurality of battery modules 11, a plurality of first DC/DC converters 12, and a first control unit.
Each of the battery modules 11 includes a plurality of cell units connected in series.
Each of the first DC/DC converters 12 is configured as a bidirectional DC/DC converter and is connected to each of the battery modules 11, and each of the first DC/DC converters 12 includes a plurality of controllable switches, which may be implemented by existing converters and is not limited to a specific DC/DC circuit topology. Specifically, in this embodiment, the low voltage side of each first DC/DC converter 12 is connected to a battery module 11, and the high voltage sides of the first DC/DC converters 12 are connected in parallel to a common terminal and connected to the inverter 20 through the common terminal, so as to realize voltage conversion between the output terminal of the corresponding battery module 11 and the common terminal. In other words, when the battery modules 11 are discharged, the voltage is boosted by the corresponding first DC/DC converter 12 and is output from the common terminal, which is a common output terminal of each battery module 11 and the first DC/DC converter 12; when the battery modules 11 are charged, the electric energy input to the common terminal is stepped down by the corresponding first DC/DC converter 12, and the common terminal is a common input terminal of each battery module 11 and the first DC/DC converter 12.
The first control unit controls each of the first DC/DC converters 12 to operate in a discharging direction (i.e., in a boost mode) when the voltage at the common terminal is lower than a first threshold. The first control unit further controls each of the first DC/DC converters 12 to operate in the charging direction (i.e., in the step-down mode) when the voltage at the common terminal is higher than a second threshold, where the first threshold is smaller than or equal to the second threshold. In this embodiment, the first threshold and the second threshold have a certain difference to provide a certain buffer space.
It should be noted that, in the term system of the present invention, the "charging direction" and the "discharging direction" both refer to the battery module 11, that is, for any DC/DC converter, the "charging direction" refers to the direction of the electric energy flowing from the current transformer 20 to the battery device 10, and conversely, the "discharging direction" refers to the direction of the electric energy flowing from the battery device 10 to the current transformer 20.
It can be seen that the battery device 10 includes a plurality of first DC/DC converters 12, and each of the first DC/DC converters 12 is coupled to a corresponding battery module 11 to convert the output voltage of the battery module 11 and then output the converted voltage in parallel, so that the capacity of the power supply system using the battery device 10 does not need to be expanded by greatly increasing the output voltage of the battery module 11. In other words, under the condition that the battery module 11 outputs a relatively low voltage, the battery device 10 can still maintain a certain output voltage during operation to meet the requirements of the power supply system; when maintenance is required, since the output voltage of the battery module 11 is not high, maintenance operation of the battery module 11 can be performed relatively safely. Thus, the above structure effectively improves the personnel safety of the battery device 10 at the time of maintenance and operation.
Moreover, since each battery module 11 of the battery device 10 is correspondingly added with a bidirectional DC/DC converter, on the basis, the present invention further provides a first control unit, which can control the working direction of each first DC/DC converter 12 and match the operation requirement of the inverter device 20 only according to the simple comparison between the voltage of the common terminal formed by connecting the high-voltage sides of the first DC/DC converters 12 in parallel and the preset threshold value. Specifically, the reason is that, since the battery device 10 is electrically coupled to the inverter device 20 to discharge or charge the inverter device 20, and the battery device 10 is connected to the inverter device 20 through the common terminal to form the above-mentioned power supply system to supply power to the outside, the operation requirement of the inverter device 20 can be mapped to the common terminal voltage, so that the first control unit can obtain the operation requirement of the inverter device 20 and correspondingly control the operation action to match the operation requirement only according to the common terminal voltage.
It should be noted that, in the present embodiment, the "operation requirement of the inverter device 20" specifically includes two situations: one is that the converter device 20 is short of supply and needs the battery device 10 to cooperate with the common power supply; the other is that the supply of the converter device 20 is excessive, and the battery device 10 is not required to be matched for supplying power together.
In other words, in practical applications of the battery device 10 of the present invention, the control of the first DC/DC in the battery device 10 can be independent of the control of the inverter device 20, and the battery device 10 can be adapted to meet the operation requirements of the power supply system without establishing a direct communication connection with the inverter device 20 through an industrial control bus and providing a complex control algorithm, which is particularly suitable for reducing the complexity of the communication layer and the control layer and the difficulty of field wiring when the battery device 10 is actually applied when the number of the first DC/DC converters 12 in the battery device 10 is large, thereby providing a good material basis for expanding the capacity of the power supply system applying the battery device 10.
In this embodiment, the battery device 10 further includes a first voltage collector 14, which is disposed at the common terminal and is used for collecting the voltage of the common terminal. In addition, the first control unit of the present embodiment includes a plurality of first controllers 13 corresponding to the first DC/DC converters 12, and each first controller 13 is connected to the first voltage collector 14 to obtain the voltage at the common terminal and is used to control the working direction of the corresponding first DC/DC converter 12. Therefore, the present embodiment can stably acquire the common terminal voltage and transmit the common terminal voltage to the control unit by providing the first voltage acquirer 14, so that the first control unit can acquire the common terminal voltage. Furthermore, configuring the first control unit to include a plurality of first controllers 13 corresponding to the respective first DC/DC converters 12 reduces the software and hardware costs of the control unit.
In this embodiment, each of the first controllers 13 controls the working direction of the corresponding first DC/DC converter 12 by modulating the duty ratio of the PWM signal, and is applicable to most DC/DC converters, and has a wide application range and a mature technology. Since it is a prior art approach to control a DC/DC converter using PWM modulation, the present invention does not specifically describe the specific processes and principles thereof.
Further, in the present embodiment, the maximum output voltage of each of the battery modules 11 is lower than 65V. The number of the battery cell units in each battery module 11 is the same, each battery cell unit is composed of two single batteries which are connected in parallel, and each single battery is a lithium battery. It can be understood that the number of the battery cell units in each battery module 11 is the same, and the occurrence of the parallel circulating current condition can be prevented to a certain extent. The maximum output voltage of each battery module 11 is lower than 65V, and the safety of personnel maintenance is guaranteed. The cell unit is formed by two single batteries connected in parallel, and the current level of the cell unit capable of being loaded is improved, so that the discharge performance of the battery device 10 is improved. The cell unit is composed of lithium batteries, in other words, the single batteries in the cell unit are all lithium batteries, so that the service life is long, and the discharge is stable.
Referring still to fig. 1, based on the battery device 10 described in the foregoing embodiment, the embodiment of the present invention further provides a control method of the battery device 10, including:
the first control unit acquires the electric quantity of each battery module 11 and the common terminal voltage. In the present embodiment, each first controller 13 obtains the common terminal voltage through the first voltage collector 14, and for the power of the battery module 11, the first controller 13 can be obtained through a conventional BMS management system provided with the battery module 11.
The first control unit controls the working state of each first DC/DC converter 12 according to the common terminal voltage and the electric quantity of each battery module 11. Specifically, in this embodiment, when the voltage at the common terminal is lower than the first threshold, each first controller 13 controls the corresponding first DC/DC converter 12 to start and operate in the discharging direction; when the voltage of the common terminal is higher than the second threshold, each first controller 13 controls the corresponding first DC/DC converter 12 to be turned on and operate in the charging direction, and controls the corresponding first DC/DC converter 12 to be turned off when the battery module 11 is fully charged. When the common terminal voltage is between the first threshold value and the second threshold value, the first controllers 13 do not perform a control operation, and thus the operating state of the first DC/DC converters 12 is maintained.
It can be seen that, based on the materials of the battery device 10, the control method takes the first control unit inside the battery device 10 as the main controller, and controls the operating state of each first DC/DC converter 12 by obtaining the electric quantity and the common terminal voltage of each battery module 11, thereby inheriting all the advantages of the battery device 10. In addition, the control method further defines that when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each first DC/DC converter 12 is kept unchanged, so that the first DC/DC converter 12 has a certain buffer space for direction switching when dealing with the common terminal voltage fluctuation, and the stability of the battery device 10 during working is improved. Further, by acquiring the amount of power of each battery module 11 to turn off the corresponding first DC/DC converter 12 when it is fully charged, it is possible to prevent the battery from being overcharged, which is particularly suitable for a lithium battery.
Referring next to fig. 2, based on the battery device 10 described in the foregoing embodiment, an embodiment of the present invention further provides a power supply system, which includes the battery device 10 and the inverter device 20.
The common terminals of the battery device 10 constitute external connection terminals for connecting external electrical equipment.
The converter device 20 has a battery terminal and comprises a DC bus, a second DC/DC converter 23 and a second control unit. The battery terminals are connected to the external connection terminals of the battery device 10. The second DC/DC converter 23 is a bidirectional DC/DC converter, and both sides of the bidirectional DC/DC converter are connected to the DC bus and the battery terminal, respectively, for voltage conversion therebetween. The second control unit is used for controlling the second DC/DC converter 23 to be kept on.
The power supply system of the embodiment includes the battery device 10 and the converter device 20, the converter device 20 is connected to the battery device 10 so that the battery module 11 is connected to the DC bus through two stages of DC/DC, and under the condition that the battery module 11 outputs a lower voltage, it can be ensured that the battery device 10 has a certain output voltage during operation to meet the requirements of the power supply system, and personnel can perform maintenance operation on the battery module 11 relatively safely, so that the power supply system uses the battery device 10 as a material basis, inherits and realizes all the advantages thereof, and is suitable for capacity expansion. In addition, the battery device 10 is connected to the battery end of the converter device 20 instead of a direct current bus, so that the existing converter device 20 does not need to be modified, and the universality is good.
Moreover, when the power supply system of the present invention applies the battery device 10, the converter device 20 is also configured in a critical manner, that is, the second control unit controls the second DC/DC converter 23 to keep on when the converter operates, so that the DC bus voltage suitable for reflecting the operation requirement of the converter device 20 can be transmitted to the common terminal voltage of the battery device 10 through the second DC/DC converter 23, and it is ensured that the battery device 10 can obtain an effective common terminal voltage capable of mapping the operation requirement of the converter device 20 at any time, and the first control unit effectively controls the first DC/DC converter 12 to match the operation requirement of the converter device 20, thereby ensuring the stable operation of the power supply system.
Specifically, as described above, the inverter device 20 of the present embodiment is the UPS system except for the conventional storage battery, that is, the inverter device 20 further includes the AC/DC converter 21 and the DC/AC converter 22. The DC sides of the AC/DC converter 21 and the DC/AC converter 22 are both connected to the DC bus, the AC side of the AC/DC converter 21 is connected to an AC power supply, and the AC side of the DC/AC converter 22 outputs an AC power. The high-voltage side of the second DC/DC converter 23 is connected to the DC bus, and the low-voltage side thereof is connected to the battery terminal. In this embodiment, the ac power supply is commercial power. Since the conversion processes such as rectification and inversion in the UPS system are prior art, the present invention does not describe them in detail.
In this embodiment, the converter device 20 further includes a second voltage collector 25, which is used for collecting the voltage of the dc bus. The second control unit is a second controller 24, which is connected to the second voltage collector 25 to obtain the dc bus voltage. The second controller 24 controls the second DC/DC converter 23 to operate in the discharging direction when the DC bus voltage is lower than a third threshold. The second controller 24 further controls the second DC/DC converter 23 to operate in the charging direction when the voltage of the DC bus is higher than a fourth threshold, where the third threshold is equal to or lower than the fourth threshold. In this embodiment, the third threshold and the fourth threshold have a certain difference. Therefore, the working direction of the second DC/DC converter 23 is controlled by collecting the DC bus voltage, and the stability is high. In other embodiments, the second control unit may also directly obtain the state of the utility power, and when the utility power is normal, the second DC/DC converter 23 is controlled to operate in the charging direction, and when the utility power is abnormal, the second DC/DC converter 23 is controlled to operate in the discharging direction, so that the response is fast.
Referring to fig. 2, based on the power supply system described in the foregoing embodiment, an embodiment of the present invention further provides a control method of the power supply system, including:
the second control unit controls the second DC/DC converter 23 to remain on. It should be noted that the keeping on refers to keeping on under each normal operation condition of the inverter device 20, for example, in this embodiment, when the inverter device 20 is normally operated, the second DC/DC converter 23 is kept on no matter whether the utility power is normal or not, and no matter whether the battery device 10 needs to be charged or not. It goes without saying that the second DC/DC converter 23 may still be switched off in case of a more serious system failure.
The second control unit obtains a direct current bus voltage. In this embodiment, the second controller 24 obtains the dc bus voltage through the second voltage collector 25.
The second control unit controls the operating direction of the second DC/DC converter 23 according to the DC bus voltage. Specifically, when the DC bus voltage is lower than the third threshold, the second controller 24 controls the second DC/DC converter 23 to operate in the discharging direction; when the DC bus voltage is higher than the fourth threshold, the second controller 24 controls the second DC/DC converter 23 to operate in the charging direction; when the DC bus voltage is between the third threshold value and the fourth threshold value, the second controller 24 does not perform a control operation, and maintains the operation direction of the second DC/DC converter 23.
The first control unit acquires the electric quantity of each battery module 11 and the common terminal voltage. In the present embodiment, each first controller 13 obtains the common terminal voltage through the first voltage collector 14, and for the power of the battery module 11, the first controller 13 can be obtained through a conventional BMS management system provided with the battery module 11.
The first control unit controls the working state of each first DC/DC converter 12 according to the common terminal voltage and the electric quantity of each battery module 11. Specifically, in this embodiment, when the voltage at the common terminal is lower than the first threshold, each first controller 13 controls the corresponding first DC/DC converter 12 to start and operate in the discharging direction; when the voltage of the common terminal is higher than the second threshold, each first controller 13 controls the corresponding first DC/DC converter 12 to be turned on and operate in the charging direction, and controls the corresponding first DC/DC converter 12 to be turned off when the battery module 11 is fully charged. When the common terminal voltage is between the first threshold value and the second threshold value, the first controllers 13 do not perform a control operation, and thus the operating state of the first DC/DC converters 12 is maintained.
In the control method of the power supply system of the embodiment, based on the materials of the power supply system, the first control unit and the second control unit are respectively used as the main controllers of the battery device 10 and the inverter device 20, and the second control unit keeps the second DC/DC converter 23 turned on to respectively control the working state of each first DC/DC converter 12 and the working direction of the second DC/DC converter 23, so that the control method inherits all the advantages of the battery device 10 and the power supply system.
In addition, the control method further defines that when the common terminal voltage is between the first threshold and the second threshold, the working state of each first DC/DC converter 12 is kept unchanged, so that the first DC/DC converter 12 has a certain buffer space in response to the direction switching of the common terminal voltage fluctuation, the stability of the battery device 10 in working is improved, and the same advantages apply to the control of the converter device 20. Further, by acquiring the amount of electricity of each battery module 11 to turn off the corresponding first DC/DC converter 12 when fully charged, it is possible to prevent the battery from being overcharged, and it is particularly suitable for a lithium battery.
Finally, the control method of the power supply system of the present embodiment is exemplarily described as a typical procedure, so that those skilled in the art can more clearly understand the structure, method and advantages of the present invention.
When the utility power is normal and each battery module 11 of the battery device 10 is fully charged, the first DC/DC converter 12 in the battery device 10 is turned off, and the second DC/DC converter 23 in the inverter device 20 is turned on and operates in the charging direction, so as to ensure that the DC bus voltage can be mapped to the common terminal through the second DC/DC converter 23.
When the mains is powered down, the AC/DC converter 21 of the inverter 20 is not operated, which causes the DC bus voltage to drop rapidly and substantially, and at this time, the second controller 24 controls the second DC/DC converter 23 to switch to the discharging direction, so as to try to raise the DC bus voltage through a certain degree of self-regulation. However, since the commercial power is turned off instead of the conventional fluctuation of the commercial power, the reduction of the DC bus voltage can be mapped to the reduction of the voltage at the common terminal, when the voltage at the common terminal drops below the first threshold, each first controller 13 turns on the corresponding first DC/DC converter 12 and operates the first DC/DC converter in the discharging direction, and the battery device 10 starts to provide power for the inverter device 20 to discharge the power.
When the utility power is restored, the AC/DC converter 21 of the converter device 20 is reactivated, which causes the DC bus voltage to rise rapidly and greatly, at this time, the second controller 24 controls the second DC/DC converter 23 to switch to the charging direction so that the voltage at the common terminal also rises correspondingly, when the voltage at the common terminal rises above the second threshold, each first controller 13 switches the corresponding first DC/DC converter 12 and makes it work in the charging direction, the battery device 10 starts to receive the electric energy provided by the converter device 20 to be charged by the same until the corresponding battery module 11 is fully charged, and the first controller 13 turns off the corresponding first DC/DC converter 12, thereby returning to the situation that the utility power is normal and each battery module 11 of the battery device 10 is fully charged.
It is understood that, whether during the charging process or the discharging process of the battery device 10, or in the case where each first DC/DC converter 12 is not turned on, when the common terminal voltage is between the first threshold value and the second threshold value, the first controller 13 does not perform corresponding control to maintain the operating state of each first DC/DC converter 12. In addition, during the discharging process of the inverter device 20 by the battery device 10, due to the variation of the dc bus voltage caused by the fluctuation of the load power, the battery device 10 is also controlled in a corresponding manner to increase or decrease the output power so as to match the more operation requirements of the inverter device 20.
The description of the above specification and examples is intended to be illustrative of the scope of the present invention and is not intended to be limiting. Modifications, equivalents and other improvements which may occur to those skilled in the art and which may be made to the embodiments of the invention or portions thereof through a reasonable analysis, inference or limited experimentation, in light of the common general knowledge, the common general knowledge in the art and/or the prior art, are intended to be within the scope of the invention.

Claims (10)

1. A battery device for electrically coupling with an inverter device; it is characterized by comprising:
each battery module comprises a plurality of battery cell units which are connected in series;
a number of DC/DC converters each configured as a bidirectional DC/DC converter; the low-voltage side of each DC/DC converter is connected with a battery module, and the high-voltage sides of the DC/DC converters are connected in parallel with a common end and are connected with the converter device through the common end;
the control unit is used for controlling each DC/DC converter to work in a discharging direction when the voltage of the common terminal is lower than a first threshold value; when the voltage of the public end is higher than a second threshold value, controlling each DC/DC converter to work in the charging direction; wherein the first threshold is less than or equal to a second threshold.
2. The battery device of claim 1, further comprising: the voltage collector is used for collecting the voltage of the public terminal;
the control unit comprises a plurality of controllers corresponding to the DC/DC converters, and each controller is connected with the voltage collector to obtain the voltage of the public terminal and is used for controlling the working direction of the corresponding DC/DC converter.
3. The battery device of claim 2, wherein: and each controller controls the working direction of the corresponding DC/DC converter by modulating the duty ratio of the PWM signal.
4. The battery device of any one of claims 1-3, wherein: the maximum output voltage of each battery module is lower than 65V; the number of the battery cell units in each battery module is the same, each battery cell unit is composed of two single batteries which are connected in parallel, and each single battery is a lithium battery.
5. A control method of a battery device, characterized in that: the battery device is as defined in any one of claims 1 to 4; the method comprises the following steps:
acquiring the electric quantity of each battery module and the voltage of the public terminal;
controlling the working state of each DC/DC converter according to the public terminal voltage and the electric quantity of each battery module; when the voltage of the public end is lower than the first threshold value, controlling each DC/DC converter to be started and work in a discharging direction; when the voltage of the public end is higher than the second threshold value, controlling each DC/DC converter to be started and work in the charging direction, and when the battery module is fully charged, controlling the corresponding DC/DC converter to be closed; and when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each DC/DC converter is kept.
6. A power supply system, comprising:
a battery device as claimed in any one of claims 1 to 4; the control unit is defined as a first control unit, the DC/DC converter is defined as a first DC/DC converter, and each first DC/DC converter is used for realizing voltage conversion between the output end of the corresponding battery module and the common end; the common terminal constitutes an external connection terminal of the battery device;
the converter device is provided with a battery end and comprises a direct current bus, a second DC/DC converter and a second control unit; the battery end is connected with the external connecting end of the battery device; the second DC/DC converter is a bidirectional DC/DC converter, and two sides of the second DC/DC converter are respectively connected with the direct current bus and the battery end and used for voltage conversion between the direct current bus and the battery end; the second control unit is used for controlling the second DC/DC converter to be kept on.
7. The power supply system of claim 6, wherein: the converter device also comprises an AC/DC converter and a DC/AC converter;
the direct current sides of the AC/DC converter and the DC/AC converter are both connected with the direct current bus, the alternating current side of the AC/DC converter is connected with an alternating current power supply, and the alternating current side of the DC/AC converter outputs alternating current;
the high-voltage side of the second DC/DC converter is connected with the direct-current bus, and the low-voltage side of the second DC/DC converter is connected with the battery end.
8. The power supply system of claim 7, wherein: the alternating current power supply at least comprises commercial power;
the second control unit acquires a mains supply state, controls the second DC/DC converter to work in a charging direction when the mains supply is normal, and controls the second DC/DC converter to work in a discharging direction when the mains supply is abnormal.
9. The power supply system of claim 7, wherein: a voltage collector of the battery device is defined as a first voltage collector;
the converter device also comprises a second voltage collector which is used for collecting the voltage of the direct current bus;
the second control unit is a second controller and is connected with the second voltage collector to obtain the voltage of the direct current bus; when the voltage of the direct current bus is lower than a third threshold value, the second DC/DC converter is controlled to work in the discharging direction; when the voltage of the direct current bus is higher than a fourth threshold value, the second DC/DC converter is controlled to work in the charging direction; wherein the third threshold is less than or equal to a fourth threshold.
10. A method of controlling a power supply system, characterized by: the power supply system is as set forth in claim 9; the method comprises the following steps:
the second control unit controls the second DC/DC converter to be kept on;
the second control unit acquires direct-current bus voltage;
the second control unit controls the working direction of the second DC/DC converter according to the voltage of the direct-current bus; when the direct-current bus voltage is lower than the third threshold, controlling the second DC/DC converter to work in a discharging direction; when the voltage of the direct current bus is higher than the fourth threshold value, controlling the second DC/DC converter to work in a charging direction; when the direct current bus voltage is between the third threshold value and the fourth threshold value, the working direction of the second DC/DC converter is kept;
the first control unit acquires the electric quantity of each battery module and the public terminal voltage;
the first control unit controls the working state of each first DC/DC converter according to the public terminal voltage and the electric quantity of each battery module; when the voltage of the public end is lower than the first threshold value, controlling each first DC/DC converter to be started and work in a discharging direction; when the voltage of the public end is higher than the second threshold value, controlling each first DC/DC converter to be started and work in the charging direction, and when the battery module is fully charged, controlling the corresponding first DC/DC converter to be stopped; and when the common terminal voltage is between the first threshold value and the second threshold value, the working state of each first DC/DC converter is maintained.
CN202110585530.7A 2021-05-27 2021-05-27 Battery device, power supply system and related control method Active CN113422421B (en)

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CN212231161U (en) * 2020-06-25 2020-12-25 北京百度网讯科技有限公司 Power supply, power supply system and data center
CN112234702A (en) * 2020-09-30 2021-01-15 漳州科华技术有限责任公司 Power supply device and UPS

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2925720A1 (en) * 2015-04-01 2016-10-01 Isolated Parallel Inc. Direct current isolated-parallel uninterruptible power supply system
CN109066964A (en) * 2018-08-29 2018-12-21 微控物理储能研究开发（深圳）有限公司 Flywheel energy storage and the double transformation UPS integrated systems, control method of online high frequency
CN209375234U (en) * 2018-12-19 2019-09-10 上海欧控电气技术有限公司 A kind of DC UPS
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